Quiet motion picture camera

ABSTRACT

A motion picture camera employs a mounting plate supported within the camera housing by means of sound-insulating connectors. All of the sound-generating moving parts are supported solely on the mounting plate. The lens, however, is mounted directly on the camera housing and is out of contact with the support plate and is thus prevented from radiating sound generated within the camera housing. The sound-insulating connectors which support the mounting plate within the camera housing are adjustable, to adjust the position of the camera &#34;movement&#34; with respect to the axis of the lens.

This application is a Continuation of my copending application Ser. No.582,698 filed June 2, 1975, now U.S. Pat. No. 4,121,886, which wasitself a Continuation of application Ser. No. 388,630 filed Aug. 15,1973, now abandoned.

This invention relates to motion picture cameras of the professionaltype used for producing motion picture photoplays provided with a soundtrack. It is essential that the cameras used for such work produce aslittle sound as possible in order to avoid recording on the sound trackunwanted sounds produced by the motion picture camera. It has beencustomary to provide a "blimp" to enclose the motion picture camera andthus minimize unwanted sounds produced by the camera. However, the blimpis awkward and cumbersome and cannot readily be used unless the camerais mounted on a tripod.

It is the principal object of this invention to provide a portablelightweight motion picture camera which can be hand-held or balanced onthe shoulder, and which produces so little sound that a blimp is notrequired. Another object is to produce such a motion picture camera inwhich the sound level produced is on the order of 27 decibels, whenoperating with the film in place.

It has been found that sound generated by the moving parts of aconventional motion picture camera is often "broadcast" by the lensassembly which is attached to the camera frame through a metal-to-metalconnection. Even though much of the sound generated by the camera"movement", film feed device, film strip itself, driving motor, etc. canbe muffled within the camera housing, a significant proportion of thesound is broadcast through the lens assembly.

In accordance with this invention, the propagation of sound through thelens assembly is substantially eliminated by mounting the lens assemblyon the camera housing, and then mounting all of the moving parts of thecamera within the housing on a single support member or plate, whichplate is secured to the camera housing only through sound-absorbingconnectors. These connectors are adjustable to permit adjustment of thealignment between the camera "movement" and the lens axis.

Other and more detailed objects and advantages will appear hereinafter.

In the drawings:

FIG. 1 is a side elevation showing a preferred form of the invention,the camera and its related parts and accessories being positioned on ashoulder mount.

FIG. 2 is a similar view showing the camera and its related parts andaccessories being positioned on a tripod mount.

FIG. 3 is a sectional elevation taken substantially on the lines 3--3 asshown in FIG. 1.

FIG. 4 is a side elevation partly broken away, taken substantially onthe lines 4--4 as shown in FIG. 3.

FIG. 5 is a sectional plan view taken substantially on the lines 5--5 asshown in FIG. 4.

FIG. 6 is a sectional elevation taken substantially on the lines 6--6 asshown in FIG. 4.

FIG. 7 is a sectional detail taken substantially on the lines 7--7 asshown in FIG. 4.

FIG. 8 is a sectional detail taken substantially on the lines 8--8 asshown in FIG. 5.

FIG. 9 is a perspective view of the support plate.

FIG. 10 is a side elevation showing the inside of the insulated door forthe camera housing.

FIG. 11 is a sectional elevation taken substantially on the lines 11--11as shown in FIG. 10.

FIG. 12 is a sectional plan view partly broken away taken substantiallyon the lines 12--12 as shown in FIG. 10.

FIG. 13 is an enlarged sectional view of a portion of FIG. 11.

Referring to the drawings, the motion picture camera generallydesignated 10 includes a housing 11 which may be supported on a shouldermount 12 as shown in FIG. 1, or on a tripod mount 13 as shown in FIG. 2.An interchangeable lens assembly 14 is mounted at the forward end of thecamera 10, together with a view finder assembly 15, a film speedindicator 16, and a film footage meter 17. A film magazine 18 may bemounted at the back face of the housing 11 as shown in FIG. 1, or,alternatively, may be mounted on the top face of the housing 11 as shownin FIG. 2. Various sizes of film magazines may be employed as shown bythe phantom lines in FIG. 2. A handle 19 mounted on a cover plate 20 isused to close an opening in the camera housing, whichever opening is notbeing used for the film magazine 18.

A mounting plate or support member 22 is positioned within the housing11 but is connected to the housing 11 only by means of foursound-insulating connectors 23, 24, 25 and 26, as shown in FIGS. 4, 5and 6. These connectors are duplicates and each includes a threaded pin27 free to turn within the metal mounting plate 22 and received withinan internally threaded sleeve 32 fixed within a hollow cylindricalelastomeric liner 28 carried in a bushing 29. The bushing 29 is threadedexternally for reception of the internal threads 30 within a boss 31formed integrally with the camera housing 11. The pin 27, sleeve 32,liner 28, bushing 29, and threads 30 are all co-axial. The mountingplate 22 is thus supported within the camera housing 11 but thesupporting means are sound-insulated so that transmission of soundbetween the mounting plate 22 and the camera housing 11 is effectivelyinhibited. Turning of the bushing 29 within the boss 31, after looseningthe pin 27 within the sleeve 32, provides lateral adjustment of themounting plate 22 with respect to the camera housing 11.

Since this lateral adjustment is provided at all four of the connectors23, 24, 25 and 26, a limited degree of tilting adjustment of themounting plate 22 about two axes is provided. These adjustments enablethe camera "movement" to be accurately aligned with respect to the axisof the lens.

All of the components of the camera which produce sound during theoperation of the camera are fixed to the mounting plate 22. Thus theelectric motor 33 is carried on spaced metal posts 34 fixed to themounting plate 22. The flange 33a carried by the posts 34 grips theoutside of the electric motor 33 only through elastomericsound-insulating ring 33b. The camera "movement" assembly 36 whichadvances the film 37 intermittently through the aperture plate 38 isalso fixed to the mounting plate 22. The drive shaft 39 which is drivenby the motor 33 through belt 40 is carried on the mounting plate 22 andserves to drive the camera movement assembly 36. The gear box 41 whichis driven by the electric motor 33 is mounted directly on the mountingplate 22 and contains gears, not shown, which turn the drive shaft 42.The axially spaced bearings 43 and 44 for the drive shaft 42 are carriedon the mounting plate 22. The film drive sprocket 45 is rotatablymounted on a support 46 fixed to the mounting plate 22 and is driven byshaft 50 which extends through opening 47 and is connected to the drivengear 48 in mesh with the driving gear 49 on the shaft 42.

The rotary shutter 51 is fixed to the shaft 42 and turns with clearancewithin the arcuate walls formed on the cross flange 54 at the forwardend of the mounting plate 22 (see FIG. 9). The path of the rotaryshutter 51 is indicated by the phantom lines in FIG. 9. The position ofthe film aperture "A" is indicated by the phantom lines in FIG. 3.

A second gear box 56 which drives the rotary mirror 57 from the forwardend of the shaft 42 is positioned forwardly of the rotary shutter 51 andis supported by the top and bottom portions of the cross flange 54 onthe mounting plate 22. This second gear box 56 does not touch the camerahousing and is not connected to it. A gear train 58 mounted within thegear box 56 serves to rotate the mirror 57 when the shaft 42 turns.

From the foregoing description it will be understood that all of thenoise-generating components of the camera are fixed on the mountingplate 22. Moreover, the camera housing 11 completely surrounds all ofthe noise-generating components. As pointed out above, the onlyconnection between the mounting plate 22 and the housing 11 is providedby the sound-insulating connectors 23, 24, 25 and 26. The lens mountingring 61 for the interchangeable lens assembly 14 is fixed to the camerahousing, or more particularly, to the cover section 62 comprising a partof the camera housing 11.

Another portion of the camera housing 11 is provided by the detachablehousing part 63. An insulated double door 64 mounted on hinges 65 alsoforms a part of the camera housing 11. The door may be swung open togain access to the film strip 37, or to the camera movement apertureplate 38, or for any other purpose. The door 64 is an assembly of aninner door 66 and an outer door 67. The inner door is separated from theouter door (no metal-to-metal contact) through the use of vibrationisolater assemblies 68 connecting the doors. The details of constructionof these vibration isolaters are shown in FIG. 13.

Closing of the double door 64 causes the seal strip 70 on the outer door67 to contact the camera housing and means are provided for tighteningthe seal strip 70 under pressure. This means includes sliding latches 71and 72 operated by rotary actuator 73 and pivotal connections 74 and 75.The projecting ends of the latches 71 and 72 move into recess 76 and 77,respectively, provided in the camera housing. The rotary actuator 73 isturned by means of stub shaft 78 and pivoted handle 79 accessibleexteriorly of the outer door 67. When the latches 71 and 72 are inlocking position as shown in FIGS. 10 and 11, pressure is applied toseal the inner door 66 on its seal strip 81. The isolation mounts 68flex sufficiently to pull the outer door 67 toward the camera housing tocompress the seal strip 70. A locking arm 82 is also pivoted to therotary actuator 73 at 75 and is slidably guided for movement into andout of a recess formed in the camera housing 11. The transverse headportion 83 on the locking arm 82 fills the recess 84 to complete thesealing of the inner door 66. The recess 84 in the camera housing isrequired to facilitate removal of the camera movement aperture plate 38for cleaning and inspection purposes.

The opening 86 in the back of the camera housing 11 is a duplicate insize and shape of the opening 87 in the upper face of the camera housing11. A manually operated cam locking mechanism 88 locks the film magazine18 in place in the opening 86 while a similar mechanism 89 locks thecover plate 20 with its handle 19 in the other opening 87. As pointedout above, the film magazine 18 may be installed in the opening 87 whilethe cover plate 20 may be installed in the opening 86, if desired. Thethreading of the film strip 37 from the film magazine 18 through one ofthe openings in the camera housing and to and from the camera movementand feed sprocket 45 is conventional. The phantom lines in FIG. 4 showhow the film strip is positioned when a film magazine 18 is positionedin the opening 87 in the camera housing.

A spring loaded threading knob 91 is mounted for both axial and rotarymovement on the back face of the camera housing 11, as shown in FIG. 5.Manual force may be applied to the knob 91 to bring the flange 92 intoengagement with the flange 93 on the end of the shaft 42. The knob 91may therefore be used to turn the shaft 42 and rotary shutter 51 to anydesired position, when the electric motor 33 is not energized.

FIG. 7 shows how a portion of the film magazine 18 is received withinone of the openings 86 and 87 in the housing 11. Guide rollers 95 and 96guide the film strip 37 in a conventional fashion.

The fragmentary view of FIG. 8 shows details of the coupling connectionby which the electric motor 33 drives the input shaft to the gear box41. Thus a flanged hub 98 driven by the motor 33 carries a plurality ofaxially extending drive pins 99 each encircled by an "O" ring 100. Thepins 99 extend into pockets 101 provided in the drive pulley 102 for thebelt 40. This drive pulley 102 is fixed to the shaft 103 which drivesthe gear box 41.

The sounds generated within the camera housing by the camera movementassembly 36, driving motor 33, gear box 41, gears 49 and 48, and thegear train 58 within the mirror driving gear box 56, as well as thesounds generated by the film strip itself--all of these sounds areeffectively smothered within the enclosing housing 11 and double door64. The sound vibrations are not transmitted to the housing 11 becauseall of the moving parts are mounted on the support plate 22. Theinterchangeable lens assembly 14 does not serve to broadcast soundsgenerated within the housing 11 because there is no contact between anyof the moving parts with the housing 11.

The camera of this invention does not require enclosure within a"blimp". A 35 mm camera of the type disclosed was found to produce onlyabout 27±1 decibels when operating with film in place.

Having fully described my invention, it is to be understood that I amnot to be limited to the details herein set forth but that my inventionis of the full scope of the appended claims.

I claim:
 1. In a motion picture camera, the combination of: a housingmember having a lens mount, a camera movement assembly enclosed withinsaid housing member, a support member within said housing member, meansfor mounting the camera movement assembly on said support member, aplurality of sound-absorbing connectors mounting said support memberwithin said housing member, said connectors each having an externallythreaded pin free to turn in one of said members, an internally threadedsleeve receiving said threaded pin, an externally threaded bushing, ahollow cylindrical elastomeric liner fixed in an annulus between saidbushing and said sleeve, said pin, sleeve, elastomeric liner, andbushing all being co-axial, each externally threaded bushing beingreceived within an internally threaded element on the other said memberwhereby turning of said bushing within said element, after looseningsaid pin within said sleeve, provides lateral adjustment of said supportmember and camera movement with respect to said camera housing and lensmount.
 2. The combination set forth in claim 1 in which said externallythreaded bushing is received in an internally threaded element on saidcamera housing member.